Offset Ink coverage, consumption

[mulo_g]

Can someone tell about ink consumption in offset printing by coated art paper and uncoated stock, if patch is printed?
e.g. how many square metres per kg.

 

[gordo]

Can someone tell about ink consumption in offset printing by coated art paper and uncoated stock, if patch is printed?
e.g. how many square metres per kg.

Read this thread: Ink Usage calculation based on coverage area

 

[mulo_g]

Unfortunately, there is no direct relationship with ink consumption and image area of the plate. It depends on what is being printed and errors can be quite large if one bases consumption on image coverage alone.

Not even plus or minus 25%. Consider patch print.

 

[Alois Senefelder]

Hello mulo-g

Don't let Erik lead you astray! ---- For your "Peace of Mind " just use the various Ink Useage Calculation Charts !!!


Regards, Alois

 

[gordo]

Ink consumption. If one wet traps ink onto another layer of ink, one does not print as much ink as if one dry trapped the ink.

Some say that only about 70% of the ink is printed when wet trapping as compared to dry trapping or the amount of ink that is printed directly on the substrate.

I doubt that the ink reduction caused by wet trapping is anything more than negligible in actual production presswork.

 

[gordo]

I am surprised you said this. What do you mean by negligible? As I stated earlier, it depends on what is being printed. If there is no overprinting, then it is not a factor. If there is a lot of overprinting, then it is a big factor.

By negligible I mean that typical production presswork the reduction in volume of ink usage caused by wet trapping is so little that it’s irrelevant.
Of course I’m speculating - you appear to be doing as well - since AFAIK there have not been any formal studies. And I’m not ready to accept the anecdotal testimony of printers. I’m surprised that you are. ;-)

One could probably model the problem in photoshop to get an idea as to the area of ink that is actually overprinted in a sampling of halftone screened images. Then use that to calculate the volume of ink represented by the areas of overprinting assuming a reduction of, perhaps, 0.3 microns of ink film thickness in the overprinted (wet trapped) areas.

Can you point to any studies that have been done along these lines?

 

[Alois Senefelder]

Hello gentlemen and fellow Lithographers,

There we have it, which I have assumed all along unless the Thesis and Presentations are not produced by Erik - they are FAKE .

All that research done by FOGRA, Pira, and other leading organizations is not worth printing the PDFs !!!! and a waste of time/experience of the
researchers at these prestigious organizations

Regards, Alois

 

[Alois Senefelder]

Hello Erik,

I'm sorry if you think that - not so! BUT you do dismiss much of the Information I post and is posted by others that

contribute to this forum, regarding the present topic under discussion - IMHO it is negligible the amount of ink saved by

Wet on Wet 4 colour lithographic printing - Might as well "Chase Rainbows"

I've had a long career in Lithographic Printing, I like to think that I have acquired some modicum of knowledge

during my 50 years.


Regards, Alois

 

[Alois Senefelder]

Hello Erik,

I do hope that this forum is broad enough to host ALL the information available, held by whatever view the person holds.

A little of my background, - 6-year apprenticeship in an average UK Printing Company, not exactly at the forefront of printing
technology, but I was lucky enough to attend the area "School of Printing Technology" What would you think when some of the
Journey-men instructed me to get a Bottle of Stale Beer which they said would cure the problem or they would delve into
their waistcoat pocket take out a pinch of some powder and add it to the Ink! - enough of me reminiscing!

So Erik onto the next item - a dreaded PDF - but from one of my early Text Books, do read the Preface by Dr V.G.W. Harrison PATRA

 

[lilon00n]

Can someone tell about ink consumption in offset printing by coated art paper and uncoated stock, if patch is printed?
e.g. how many square metres per kg.

you can get Area % free online with www.ink-cover.com
Try it, it's free.